Controlled delivery drive mechanisms for drug delivery pumps

ABSTRACT

A controlled delivery drive mechanism includes a drive housing, a piston, and a biasing member initially retained in an energized state and is configured to bear upon an interface surface of the piston. The piston is configured to translate a plunger seal and a barrel. A tether is connected between the piston and the winch drum to restrain the free expansion of the biasing member and the free axial translation of the piston upon which the biasing member bears upon. The drive mechanism may further include a gear assembly and an escapement regulating mechanism configured to control the rotation of the gear assembly to release the tether from the winch drum. The metering of the tether by the escapement regulating mechanism controls the rate or profile of drug delivery to a user.

RELATED APPLICATION

This application claims the benefit of U.S. Provisional Application No.62/381,377, filed on Aug. 30, 2016. The entire teachings of thisapplication are incorporated herein by reference.

FIELD

This invention relates to drug delivery pumps. More particularly, thisinvention relates to drive mechanisms for the controlled delivery ofdrug substances, drug delivery pumps with controlled delivery drivemechanisms, the methods of operating such devices, and the methods ofassembling such devices.

BACKGROUND

Parenteral delivery of various drugs, i.e., delivery by means other thanthrough the digestive track, has become a desired method of drugdelivery for a number of reasons. This form of drug delivery byinjection may enhance the effect of the substance being delivered andensure that the unaltered medicine reaches its intended site at asignificant concentration. Similarly, undesired side effects associatedwith other routes of delivery, such as systemic toxicity, canpotentially be avoided through parenteral delivery. By bypassing thedigestive system of a mammalian patient, one can avoid degradation ofthe active ingredients caused by the catalytic enzymes in the digestivetract and liver and ensure that a necessary amount of drug, at a desiredconcentration, reaches the targeted site.

Traditionally, manually operated syringes and injection pens have beenemployed for delivering parenteral drugs to a patient. More recently,parenteral delivery of liquid medicines into the body has beenaccomplished by administering bolus injections using a needle andreservoir, continuously by gravity driven dispensers, or via transdermalpatch technologies. Bolus injections often imperfectly match theclinical needs of the patient, and usually require larger individualdoses than are desired at the specific time they are given. Continuousdelivery of medicine through gravity-feed systems compromises thepatient's mobility and lifestyle, and limits the therapy to simplisticflow rates and profiles. Another form of drug delivery, transdermalpatches, similarly has its restrictions. Transdermal patches oftenrequire specific molecular drug structures for efficacy, and the controlof the drug administration through a transdermal patch is severelylimited.

Ambulatory infusion pumps have been developed for delivering liquidmedicaments to a patient. These infusion devices have the ability tooffer sophisticated fluid delivery profiles accomplishing bolusrequirements, continuous infusion and variable flow rate delivery. Theseinfusion capabilities usually result in better efficacy of the drug andtherapy and less toxicity to the patient's system. Currently availableambulatory infusion devices are expensive, difficult to program andprepare for infusion, and tend to be bulky, heavy and very fragile.Filling these devices can be difficult and require the patient to carryboth the intended medication as well as filling accessories. The devicesoften require specialized care, maintenance, and cleaning to assureproper functionality and safety for their intended long-term use, andare not cost-effective for patients or healthcare providers.

As compared to syringes and injection pens, pump type delivery devicescan be significantly more convenient to a patient, in that doses of thedrug may be calculated and delivered automatically to a patient at anytime during the day or night. Furthermore, when used in conjunction withmetabolic sensors or monitors, pumps may be automatically controlled toprovide appropriate doses of a fluidic medium at appropriate times ofneed, based on sensed or monitored metabolic levels. As a result, pumptype delivery devices have become an important aspect of modern medicaltreatments of various types of medical conditions, such as diabetes, andthe like.

While pump type delivery systems have been utilized to solve a number ofpatient needs, manually operated syringes and injection pens oftenremain a preferred choice for drug delivery as they now provideintegrated safety features and can easily be read to identify the statusof drug delivery and the end of dose dispensing. However, manuallyoperated syringes and injections pens are not universally applicable andare not preferred for delivery of all drugs. There remains a need for anadjustable (and/or programmable) infusion system that is precise andreliable and can offer clinicians and patients a small, low cost, lightweight, simple to use alternative for parenteral delivery of liquidmedicines.

SUMMARY

Drive mechanisms for the controlled delivery of drug substances areprovided, as well as drug delivery pumps with controlled delivery drivemechanisms, methods of operating such devices, and methods of assemblingsuch devices. Notably, the drive mechanisms of the present inventioncontrol a rate of drug delivery by metering, providing resistance, orotherwise preventing free axial translation of a plunger seal utilizedto force a drug substance out of a drug container. Such drive mechanismsalso provide for a smaller footprint, enabling their use in more compactdrug delivery pumps, while also being capable of delivering drugsubstances at variable rates. The controlled delivery drive mechanismsof the present invention may be pre-configurable or dynamicallyconfigurable, such as by control by the power and control system, tomeet desired delivery rates or profiles, as explained in detail below.Additionally, drive mechanisms of the present invention can provideintegrated status indication features to provide feedback to a userbefore, during, and after drug delivery. For example, the user may beprovided an initial feedback to identify that the system is operationaland ready for drug delivery. Upon activation, the system may thenprovide one or more drug delivery status indications to the user. Atcompletion of drug delivery, the drive mechanism and drug pump mayprovide an end-of-dose indication. Because the end-of-dose indication isrelated to the physical end of axial translation of one or morecomponents of the drive mechanism, the drive mechanism and drug pumpprovide a true end-of-dose indication to the user. Through thesemechanisms, confirmation of drug dose delivery can accurately beprovided to the user or administrator. Accordingly, the novel devices ofthe present invention alleviate one or more of the problems associatedwith prior art devices, such as those referred to above.

In a first embodiment, the present invention provides a controlleddelivery drive mechanism which includes a drive housing, a piston, andone or more biasing members, wherein the one or more biasing members areinitially retained in an energized state and is configured to bear uponan interface surface of the piston. The piston is configured totranslate substantially axially within a drug container having a plungerseal and a barrel. A tether is connected at one end to the piston and atanother end to a winch drum of a regulating mechanism. The tetherrestrains the free expansion of the biasing member from its initialenergized state, thereby also restraining the free axial translation ofthe piston upon which the biasing member bears upon. The tether isconfigured to be released from a winch drum of the regulating mechanism,providing controlled expansion of the biasing member.

The drug container may contain a drug fluid within a drug chamber fordelivery to a user. Optionally, a cover sleeve may be utilized betweenthe biasing member and the interface surface of the piston to hide theinterior components of the barrel (namely, the piston and the biasingmember) from view during operation of the drive mechanism.

In at least one embodiment, the regulating mechanism is an escapementregulating mechanism coupled to, or acting with, the winch drum. Theescapement regulating mechanism may further include a gear train havingone or more gears, wherein the rotation of at least one gear of the geartrain is coupled to the rotation of the winch drum. In a particularembodiment, the escapement regulating mechanism further includes a leverand an escape wheel configured to engage and meter the rotationalmovement of the gear train. The lever has pins and a prong, wherein theprong movably engages a post and is configured to removably engage animpulse pin of a balance wheel, and wherein the balance wheel engagesand is capable of oscillating around a post in combination with a hairspring. An electromechanical actuator such as a motor or solenoid mayadditionally be used to control the oscillation and/or rotation of thebalance wheel. For example, a DC or stepper motor may be used, or alinear or rotary solenoid may be used. The escape wheel is a compoundgear having escape teeth around the circumference of a large diameterescape gear and a small diameter gear configured to engage and meter thegear train. The metering of the gear train and/or winch drum by anescapement regulating mechanism controls the rate or profile of drugdelivery to a user.

The gear train may include a winch gear coupled to a winch drum uponwhich the tether may be releasably wound. The winch gear may beconfigured to engage a first compound gear, such that rotation of thewinch gear and the small gear of the first compound gear are linked. Thegear assembly may additionally include a second compound gear, whereinthe large gear of the first compound gear is engaged with the small gearof the second compound gear. The large gear of the second compound gearmay be engaged with a gear of the escape wheel such that rotation of thesecond compound gear and escape wheel are coupled. In this way rotationof the escape wheel is coupled to rotation of the winch drum and canthereby control the release of the tether from the winch drum to meterthe free expansion of the biasing member from its initial energizedstate and the free axial translation of the piston upon which thebiasing member bears upon. The metering of the tether by the regulatingmechanism controls the rate or profile of drug delivery to a user. Thepiston may be one or more parts and connects to a distal end of thetether.

In yet another embodiment, the drive mechanism may include a statusreader configured to read or recognize one or more corresponding statustriggers. The status triggers may be incrementally spaced on the tether,wherein, during operation of the drive mechanism, interaction betweenthe status reader and the status triggers transmit a signal to a powerand control system to provide feedback to a user. The status reader maybe an optical status reader and the corresponding status triggers areoptical status triggers, an electromechanical status reader and thecorresponding status triggers are electromechanical status triggers, ora mechanical status reader and the corresponding status triggers aremechanical status triggers.

In a further embodiment, the present invention provides a drug deliverypump with controlled drug delivery. The drug delivery pump includes ahousing and/or an assembly platform, upon which an activation mechanism,an insertion mechanism, a fluid pathway connection, a power and controlsystem, and a controlled delivery drive mechanism may be mounted. Thedrive mechanism includes a drive housing, a piston, and a biasingmember, wherein the biasing member is initially retained in an energizedstate and is configured to bear upon an interface surface of the piston.The piston is configured to translate substantially axially within adrug container having a plunger seal and a barrel. A tether is connectedat one end to the piston and at another end to a winch drum of adelivery regulating mechanism, wherein the tether restrains the freeexpansion of the biasing member from its initial energized state and thefree axial translation of the piston upon which the biasing member bearsupon. The drug container may contain a drug fluid within a drug chamberfor delivery to a user. Optionally, a cover sleeve may be utilizedbetween the biasing member and the interface surface of the piston tohide the interior components of the barrel (namely, the piston and thebiasing member) from view during operation of the drive mechanism. Thetether is configured to be released from a winch drum of the deliveryregulating mechanism to meter the free expansion of the biasing memberfrom its initial energized state and the free axial translation of thepiston upon which the biasing member bears upon.

In another embodiment, the drug pump further includes a gear assembly.The gear assembly may include a winch gear connected to a winch drumupon which the tether may be releasably wound, rotation of the winchdrum releases the tether from the winch drum to meter the free expansionof the biasing member from its initial energized state and the freeaxial translation of the piston upon which the biasing member bearsupon. The metering of the tether controls the rate or profile of drugdelivery to a user. The piston may be one or more parts and connects toa distal end of the tether. The winch drum is coupled to a regulatingmechanism which controls rotation of the winch drum and hence meteringof the translation of the piston.

The drug pump may utilize the regulating mechanism described above inthe first embodiment, which configuration utilizes an escapementregulating mechanism to control the metering of the tether. Theescapement regulating mechanism may further include a gear train havingone or more gears. In a particular embodiment, the escapement regulatingmechanism further includes a lever and an escape wheel configured toengage and meter the rotational movement of the gear train. The leverhas pins and a prong, wherein the prong movably engages a post and isconfigured to removably engage an impulse pin of a balance wheel, andwherein the balance wheel engages and is capable of oscillating around apost in combination with a hair spring. A motor, such as a DC motor orstepper motor, or a linear or rotary solenoid may additionally be usedto control the oscillation and/or rotation of the balance wheel. Theescape wheel is a compound gear having escape teeth around thecircumference of a large diameter escape gear and a small diameter gearconfigured to engage and meter the gear train. The metering of the geartrain by an escapement regulating mechanism controls the rate or profileof drug delivery to a user. The piston is configured to contact andaxially translate the plunger seal within the barrel.

In yet another embodiment, the drug pump may include a status readerconfigured to read or recognize one or more corresponding statustriggers. The status triggers may be incrementally spaced on the tether,wherein, during operation of the drive mechanism, interaction betweenthe status reader and the status triggers transmit a signal to a powerand control system to provide feedback to a user. The status reader maybe an optical status reader and the corresponding status triggers areoptical status triggers, an electromechanical status reader and thecorresponding status triggers are electromechanical status triggers, ora mechanical status reader and the corresponding status triggers aremechanical status triggers.

In another embodiment, the power and control system of the drug pump isconfigured to receive one or more inputs to meter the release of thetether by the winch drum and thereby permit axial translation of thepiston by the biasing member to translate a plunger seal within abarrel. The one or more inputs may be provided by the actuation of theactivation mechanism, a control interface, and/or a remote controlmechanism. The power and control system may be configured to receive oneor more inputs to adjust the restraint provided by the tether and winchdrum on the free axial translation of the piston upon which the biasingmember bears upon to meet a desired drug delivery rate or profile, tochange the dose volume for delivery to the user, and/or to otherwisestart, stop, or pause operation of the drive mechanism.

A method of assembling a drug delivery pump includes attaching acontrolled delivery drive mechanism, an insertion mechanism, a fluidpathway connection, and a power and control system to an assemblyplatform and/or a housing of the drug pump.

A method of operating a drug delivery pump includes restrainingexpansion of at least one biasing member with a tether and meteringrelease of the tether with an escapement regulating mechanism. Thetether is connected at one end to a piston having an interface surfaceand at another end to a winch drum. The biasing member, initiallyretained in an energized state, is configured to bear upon the interfacesurface of the piston, and, upon metered release of the tether by thewinch drum, the biasing member is configured to cause release of a drugfrom the pump.

The novel embodiments of the present invention provide for drivemechanisms that are capable of metering, providing resistance, orotherwise preventing free axial translation of a plunger seal utilizedto force a drug substance out of a drug container and, thereby, controla rate of delivery of drug substances. Embodiments of the presentinvention, in which a tether is provided to restrain expansion of abiasing member, also provide for a more compact design than drivemechanisms requiring a lengthier piston. In addition, as force totranslate a plunger seal is provided by the biasing member, with thebiasing member being restrained by tether that is metered by anescapement regulating mechanism, power and control systems are optionalin drug delivery pumps of the present invention, providing for an evenfurther space-saving design.

The novel control delivery drive mechanisms are additionally capable ofproviding the incremental status of the drug delivery before, during,and after operation of the device. Throughout this specification, unlessotherwise indicated, “comprise,” “comprises,” and “comprising,” orrelated terms such as “includes” or “consists of,” are used inclusivelyrather than exclusively, so that a stated integer or group of integersmay include one or more other non-stated integers or groups of integers.As will be described further below, the embodiments of the presentinvention may include one or more additional components which may beconsidered standard components in the industry of medical devices. Forexample, the embodiments may include one or more batteries utilized topower the motor, drive mechanisms, and drug pumps of the presentinvention. The components, and the embodiments containing suchcomponents, are within the contemplation of the present invention andare to be understood as falling within the breadth and scope of thepresent invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The following non-limiting embodiments of the invention are describedherein with reference to the following drawings, wherein:

FIG. 1A shows an isometric view of a drug delivery pump having acontrolled delivery drive mechanism, according to one embodiment of thepresent invention;

FIG. 1B shows an isometric view of the interior components of the drugdelivery pump shown in FIG. 1A (shown without the adhesive patch);

FIG. 1C shows an isometric view of the bottom of the drug delivery pumpshown in FIG. 1A (shown without the adhesive patch);

FIG. 2A shows an exploded view, along an axis “A,” of a drive mechanismand drug container, of one embodiment of the present invention;

FIG. 2B shows an exploded view, along an axis “B,” of one embodiment ofthe present invention (biasing member, cover sleeve, plunger seal,barrel, and cap are not shown for clarity);

FIG. 3A shows an isometric view of a controlled delivery drivemechanism, according to at least one embodiment of the presentinvention;

FIG. 3B shows an isometric view of a controlled delivery drivemechanism, according to at least one embodiment of the present invention(the piston is shown exploded to illustrate attachment of tether);

FIGS. 4A-4C shows an enlarged view of an escapement regulating mechanismof a drive mechanism, according to at least one embodiment of thepresent invention;

FIGS. 4D-4H shows the progression of the escapement regulatingmechanism, according to the embodiment shown in FIGS. 4A-4C, duringoperation;

FIG. 5A shows an isometric view of the drive mechanism and drugcontainer shown in FIG. 2 in an initial inactive state;

FIG. 5B shows an isometric view of the drive mechanism shown in FIG. 2as the mechanism completes drug delivery;

FIG. 6A shows a cross-sectional view of the drive mechanism shown inFIG. 2 in an initial inactive state;

FIG. 6B shows a cross-sectional view of the drive mechanism shown inFIG. 2 in an actuated state as the mechanism controls the rate orprofile of drug delivery;

FIG. 6C shows a cross-sectional view of the drive mechanism shown inFIG. 2 as the mechanism completes drug delivery and, optionally,performs a compliance push to ensure completion of drug delivery.

FIG. 7 shows an isometric view of another configuration of interiorcomponents of a drug delivery pump.

DETAILED DESCRIPTION

The present invention provides drive mechanisms for the controlleddelivery of drug substances and drug delivery pumps that incorporatesuch controlled delivery drive mechanisms. The drive mechanisms of thepresent invention control the rate of drug delivery by metering,providing resistance, or otherwise preventing free axial translation ofthe plunger seal utilized to force a drug substance out of a drugcontainer and, thus, are capable of delivering drug substances atvariable rates and/or delivery profiles. The drive mechanisms include atether configured to restrain expansion of a biasing member, therebyproviding for a more compact design than drive mechanisms requiring alengthier piston. Additionally, the drive mechanisms of the presentinvention can provide for integrated status indication features, such aswith status triggers located on a tether of the device, which canprovide feedback to the user before, during, and after drug delivery.For example, the user may be provided an initial feedback to identifythat the system is operational and ready for drug delivery. Uponactivation, the system may then provide one or more drug delivery statusindications to the user. At completion of drug delivery, the drivemechanism and drug pump may provide an end-of-dose indication.

As used herein to describe the drive mechanisms, drug delivery pumps, orany of the relative positions of the components of the presentinvention, the terms “axial” or “axially” refer generally to alongitudinal axis “A” around which the drive mechanisms are preferablypositioned, although not necessarily symmetrically there-around. Theterm “radial” refers generally to a direction normal to axis A. Theterms “proximal,” “rear,” “rearward,” “back,” or “backward” refergenerally to an axial direction in the direction “P”. The terms“distal,” “front,” “frontward,” “depressed,” or “forward” refergenerally to an axial direction in the direction “D”. As used herein,the term “glass” should be understood to include other similarlynon-reactive materials suitable for use in a pharmaceutical gradeapplication that would normally require glass, including but not limitedto certain non-reactive polymers such as cyclic olefin copolymers (COC)and cyclic olefin polymers (COP). The term “plastic” may include boththermoplastic and thermosetting polymers. Thermoplastic polymers can bere-softened to their original condition by heat; thermosetting polymerscannot. As used herein, the term “plastic” refers primarily to moldablethermoplastic polymers such as, for example, polyethylene andpolypropylene, or an acrylic resin, that also typically contain otheringredients such as curatives, fillers, reinforcing agents, colorants,and/or plasticizers, etc., and that can be formed or molded under heatand pressure. As used herein, the term “plastic” is not meant to includeglass, non-reactive polymers, or elastomers that are approved for use inapplications where they are in direct contact with therapeutic liquidsthat can interact with plastic or that can be degraded by substituentsthat could otherwise enter the liquid from plastic. The term“elastomer,” “elastomeric” or “elastomeric material” refers primarily tocross-linked thermosetting rubbery polymers that are more easilydeformable than plastics but that are approved for use withpharmaceutical grade fluids and are not readily susceptible to leachingor gas migration under ambient temperature and pressure. “Fluid” refersprimarily to liquids, but can also include suspensions of solidsdispersed in liquids, and gasses dissolved in or otherwise presenttogether within liquids inside the fluid-containing portions of the drugpumps. According to various aspects and embodiments described herein,reference is made to a “biasing member”, such as in the context of oneor more biasing members for asserting force on a plunger seal. It willbe appreciated that the biasing member may be any member that is capableof storing and releasing energy. Non-limiting examples include a spring,such as for example a coiled spring, a compression or extension spring,a torsional spring, or a leaf spring, a resiliently compressible orelastic band, or any other member with similar functions. In at leastone embodiment of the present invention, the biasing member is a spring,preferably a compression spring.

The novel devices of the present invention provide drive mechanisms withintegrated status indication and drug delivery pumps which incorporatesuch drive mechanisms. Such devices are safe and easy to use, and areaesthetically and ergonomically appealing for self-administeringpatients. The devices described herein incorporate features which makeactivation, operation, and lock-out of the device simple for evenuntrained users. The novel devices of the present invention providethese desirable features without any of the problems associated withknown prior art devices. Certain non-limiting embodiments of the noveldrug delivery pumps, drive mechanisms, and their respective componentsare described further herein with reference to the accompanying figures.

As used herein, the term “pump” is intended to include any number ofdrug delivery systems which are capable of dispensing a fluid to a userupon activation. Such drug delivery systems include, for example,injection systems, infusion pumps, bolus injectors, and the like. FIGS.1A-1C show an exemplary drug delivery device according to at least oneembodiment of the present invention. The drug delivery device may beutilized to administer delivery of a drug treatment into a body of auser. As shown in FIGS. 1A-1C, the drug pump 10 includes a pump housing12. Pump housing 12 may include one or more housing subcomponents whichare fixedly engageable to facilitate easier manufacturing, assembly, andoperation of the drug pump. For example, drug pump 10 includes a pumphousing 12 which includes an upper housing 12A and a lower housing 12B.The drug pump may further include an activation mechanism 14, a statusindicator 16, and a window 18. Window 18 may be any translucent ortransmissive surface through which the operation of the drug pump may beviewed. As shown in FIG. 1B, drug pump 10 further includes assemblyplatform 20, drive mechanism 100 having drug container 50, insertionmechanism 200, and a fluid pathway connection 300. An alternativeconfiguration of a drug pump 10 is shown in FIG. 7, with the drug pump10 further including a power and control system 400. A sterile fluidconduit 30 located at the fluid pathway connection 300 and leading toinsertion mechanism 200 is also visible in FIG. 7. One or more of thecomponents of such drug pumps may be modular in that they may be, forexample, pre-assembled as separate components and configured intoposition onto the assembly platform 20 of the drug pump 10 duringmanufacturing.

The pump housing 12 contains all of the device components and provides ameans of removably attaching the device 10 to the skin of the user. Thepump housing 12 also provides protection to the interior components ofthe device 10 against environmental influences. The pump housing 12 isergonomically and aesthetically designed in size, shape, and relatedfeatures to facilitate easy packaging, storage, handling, and use byusers who may be untrained and/or physically impaired. Furthermore, theexternal surface of the pump housing 12 may be utilized to provideproduct labeling, safety instructions, and the like. Additionally, asdescribed above, housing 12 may include certain components, such asstatus indicator 16 and window 18, which may provide operation feedbackto the user.

In at least one embodiment, the drug pump 10 provides an activationmechanism 14 that is displaced by the user to trigger the start commandto the power and control system. In a preferred embodiment, theactivation mechanism is a start button 14 that is located through thepump housing 12, such as through an aperture between upper housing 12Aand lower housing 12B, and which contacts a control arm 40 of the powerand control system. In at least one embodiment, the start button 14 maybe a push button, and in other embodiments, may be an on/off switch, atoggle, or any similar activation feature known in the art. The pumphousing 12 also provides a status indicator 16 and a window 18. In otherembodiments, one or more of the activation mechanism 14, the statusindicator 16, the window 18, and combinations thereof may be provided onthe upper housing 12A or the lower housing 12B such as, for example, ona side visible to the user when the drug pump 10 is placed on the bodyof the user. Housing 12 is described in further detail hereinafter withreference to other components and embodiments of the present invention.

Drug pump 10 is configured such that, upon activation by a user bydepression of the activation mechanism, the drug pump is initiated to:insert a fluid pathway into the user; enable, connect, or open necessaryconnections between a drug container, a fluid pathway, and a sterilefluid conduit; and force drug fluid stored in the drug container throughthe fluid pathway and fluid conduit for delivery into a user. One ormore optional safety mechanisms may be utilized, for example, to preventpremature activation of the drug pump. For example, an optional on-bodysensor 24 (shown in FIG. 1C) may be provided in one embodiment as asafety feature to ensure that the power and control system, or theactivation mechanism 14, cannot be engaged unless the drug pump 10 is incontact with the body of the user. In one such embodiment, the on-bodysensor 24 is located on the bottom of lower housing 12B where it maycome in contact with the user's body. Upon displacement of the on-bodysensor 24, depression of the activation mechanism is permitted.Accordingly, in at least one embodiment the on-body sensor 24 is amechanical safety mechanism, such as for example a mechanical lock out,that prevents triggering of the drug pump 10 by the activation mechanism14. In another embodiment, the on-body sensor may be anelectro-mechanical sensor such as a mechanical lock out that sends asignal to the power and control system to permit activation. In stillother embodiments, the on-body sensor can be electrically based such as,for example, a capacitive- or impedance-based sensor which must detecttissue before permitting activation of the power and control system.These concepts are not mutually exclusive and one or more combinationsmay be utilized within the breadth of the present invention to prevent,for example, premature activation of the drug pump. In a preferredembodiment, the drug pump 10 utilizes one or more mechanical on-bodysensors. Additional integrated safety mechanisms are described hereinwith reference to other components of the novel drug pumps.

Power and Control System:

As will be described further below, as force to translate a plunger seal60 is provided by at least one biasing member 122 a, 122 b (FIG. 2A),power and control systems are optional in drug delivery pumps of thepresent invention.

The power and control system 400 includes a power source, which providesthe energy for various electrical components within the drug pump, oneor more feedback mechanisms, a microcontroller, a circuit board, one ormore conductive pads, and one or more interconnects. Other componentscommonly used in such electrical systems may also be included, as wouldbe appreciated by one having ordinary skill in the art. The one or morefeedback mechanisms may include, for example, audible alarms such aspiezo alarms and/or light indicators such as light emitting diodes(LEDs). The microcontroller may be, for example, a microprocessor. Thepower and control system controls several device interactions with theuser and interfaces with the drive mechanism 100. In one embodiment, thepower and control system interfaces with the control arm 40 to identifywhen the on-body sensor 24 and/or the activation mechanism 14 have beenactivated. The power and control system may also interface with thestatus indicator 16 of the pump housing 12, which may be a transmissiveor translucent material which permits light transfer, to provide visualfeedback to the user. The power and control system interfaces with thedrive mechanism 100 through one or more interconnects to relay statusindication, such as activation, drug delivery, and end-of-dose, to theuser. Such status indication may be presented to the user via auditorytones, such as through the audible alarms, and/or via visual indicators,such as through the LEDs. In a preferred embodiment, the controlinterfaces between the power and control system and the other componentsof the drug pump are not engaged or connected until activation by theuser. This is a desirable safety feature that prevents accidentaloperation of the drug pump and may additionally maintain the energycontained in the power source during storage, transportation, and thelike.

The power and control system may be configured to provide a number ofdifferent status indicators to the user. For example, the power andcontrol system may be configured such that after the on-body sensorand/or trigger mechanism have been pressed, the power and control systemprovides a ready-to-start status signal via the status indicator 16 ifdevice start-up checks provide no errors. After providing theready-to-start status signal and, in an embodiment with the optionalon-body sensor, if the on-body sensor remains in contact with the bodyof the user, the power and control system will power the drive mechanism100 to begin delivery of the drug treatment through the fluid pathwayconnection 300 and sterile fluid conduit 30. In a preferred embodimentof the present invention, the insertion mechanism 200 and the fluidpathway connection 300 may be caused to activate directly by useroperation of the activation mechanism 14. During the drug deliveryprocess, the power and control system is configured to provide adispensing status signal via the status indicator 16. After the drug hasbeen administered into the body of the user and after the end of anyadditional dwell time, to ensure that substantially the entire dose hasbeen delivered to the user, the power and control system may provide anokay-to-remove status signal via the status indicator 16. This may beindependently verified by the user by viewing the drive mechanism anddrug dose delivery through the window 18 of the pump housing 12.Additionally, the power and control system may be configured to provideone or more alert signals via the status indicator 16, such as forexample alerts indicative of fault or operation failure situations.

The power and control system may additionally be configured to acceptvarious inputs from the user to dynamically control the drive mechanisms100 to meet a desired drug delivery rate or profile. For example, thepower and control system may receive inputs, such as from partial orfull activation, depression, and/or release of the activation mechanism14, to set, initiate, stop, or otherwise adjust the control of the drivemechanism 100 via the power and control system to meet the desired drugdelivery rate or profile. Similarly, the power and control system may beconfigured to receive such inputs to adjust the drug dose volume; toprime the drive mechanism, fluid pathway connection, and fluid conduit;and/or to start, stop, or pause operation of the drive mechanism 100.Such inputs may be received by the user directly acting on the drug pump10, such as by use of the activation mechanism 14 or a different controlinterface, or the system 400 may be configured to receive such inputsfrom a remote control device. Additionally or alternatively, such inputsmay be pre-programmed.

Other power and control system configurations may be utilized with thenovel drug pumps of the present invention. For example, certainactivation delays may be utilized during drug delivery. As mentionedabove, one such delay optionally included within the systemconfiguration is a dwell time which ensures that substantially theentire drug dose has been delivered before signaling completion to theuser. Similarly, activation of the device may require a delayeddepression (i.e., pushing) of the activation mechanism 14 of the drugpump 10 prior to drug pump activation. Additionally, the system mayinclude a feature which permits the user to respond to the end-of-dosesignals and to deactivate or power-down the drug pump. Such a featuremay similarly require a delayed depression of the activation mechanism,to prevent accidental deactivation of the device. Such features providedesirable safety integration and ease-of-use parameters to the drugpumps. An additional safety feature may be integrated into theactivation mechanism to prevent partial depression and, therefore,partial activation of the drug pumps. For example, the activationmechanism and/or power and control system may be configured such thatthe device is either completely off or completely on, to prevent partialactivation. Such features are described in further detail hereinafterwith regard to other aspects of the novel drug pumps.

Fluid Pathway Connection:

A number of fluid pathway connections may be utilized within theembodiments of the present invention. Generally, a suitable fluidpathway connection includes a sterile fluid conduit, a piercing member,and a sterile sleeve attached to a drug container or a slidingpierceable seal integrated within a drug container. The fluid pathwayconnection may further include one or more flow restrictors. Upon properactivation of the device 10, the fluid pathway connection 300 is enabledto connect the sterile fluid conduit 30 to the drug container of thedrive mechanism 100. Such connection may be facilitated by a piercingmember, such as a needle, penetrating a pierceable seal of the drugcontainer of the drive mechanism 100. The sterility of this connectionmay be maintained by performing the connection within a flexible sterilesleeve. Upon substantially simultaneous activation of the insertionmechanism, the fluid pathway between drug container and insertionmechanism is complete to permit drug delivery into the body of the user.

In at least one embodiment of the present invention, the piercing memberof the fluid pathway connection is caused to penetrate the pierceableseal of the drug container of the drive mechanism by direct action ofthe user, such as by depression of the activation mechanism by the user.For example, the activation mechanism itself may bear on the fluidpathway connection such that displacement of the activation mechanismfrom its original position also causes displacement of the fluid pathwayconnection. In one such embodiment, the fluid pathway connection may besubstantially similar to that described in International PatentApplication No. PCT/US2012/054861, which is included by reference hereinin its entirety for all purposes. According to such an embodiment, theconnection is enabled by the user depressing the activation mechanismand, thereby, driving the piercing member through the pierceable seal,because this prevents fluid flow from the drug container until desiredby the user. In such an embodiment, a compressible sterile sleeve may befixedly attached between the cap of the drug container and theconnection hub of the fluid pathway connection. The piercing member mayreside within the sterile sleeve until a connection between the fluidconnection pathway and the drug container is desired. The sterile sleevemay be sterilized to ensure the sterility of the piercing member and thefluid pathway prior to activation.

Alternatively, the fluid pathway connection may be integrated into adrug container as described in International Patent Application No.PCT/US2013/030478, for example, which is included by reference herein inits entirety for all purposes. According to such an embodiment, a drugcontainer may have a drug chamber within a barrel between a pierceableseal and a plunger seal. A drug fluid is contained in the drug chamber.Upon activation of the device by the user, a drive mechanism asserts aforce on a plunger seal contained in the drug container. As the plungerseal asserts a force on the drug fluid and any air/gas gap or bubble, acombination of pneumatic and hydraulic pressure builds by compression ofthe air/gas and drug fluid and the force is relayed to the slidingpierceable seal. The sliding pierceable seal is caused to slide towardsthe cap, causing it to be pierced by the piercing member retained withinthe integrated sterile fluid pathway connection. Accordingly, theintegrated sterile fluid pathway connection is connected (i.e., thefluid pathway is opened) by the combination pneumatic/hydraulic force ofthe air/gas and drug fluid within the drug chamber created by activationof a drive mechanism. Once the integrated sterile fluid pathwayconnection is connected or opened, drug fluid is permitted to flow fromthe drug container, through the integrated sterile fluid pathwayconnection, sterile fluid conduit, and insertion mechanism, and into thebody of the user for drug delivery. In at least one embodiment, thefluid flows through only a manifold and a cannula and/or needle of theinsertion mechanism, thereby maintaining the sterility of the fluidpathway before and during drug delivery.

Regardless of the fluid pathway connection utilized by the drug pump,the drug pump is capable of delivering a range of drugs with differentviscosities and volumes. The drug pump is capable of delivering a drugat a controlled flow rate (speed) and/or of a specified volume. In oneembodiment, the drug delivery process is controlled by one or more flowrestrictors within the fluid pathway connection and/or the sterile fluidconduit. In other embodiments, other flow rates may be provided byvarying the geometry of the fluid flow path or delivery conduit, varyingthe speed at which a component of the drive mechanism advances into thedrug container to dispense the drug therein, or combinations thereof.Still further details about the fluid pathway connection 300 and thesterile fluid conduit 30 are provided hereinafter in later sections inreference to other embodiments.

Insertion Mechanism:

A number of insertion mechanisms may be utilized within the drug pumpsof the present invention. The pump-type delivery devices of the presentinvention may be connected in fluid flow communication to a patient oruser, for example, through any suitable hollow tubing. A solid boreneedle may be used to pierce the skin of the patient and place a hollowcannula at the appropriate delivery position, with the solid bore needlebeing removed or retracted prior to drug delivery to the patient. Asstated above, the fluid can be introduced into the body through anynumber of means, including but not limited to: an automatically insertedneedle, cannula, micro-needle array, or infusion set tubing. A number ofmechanisms may also be employed to activate the needle insertion intothe patient. For example, a biasing member such as a spring may beemployed to provide sufficient force to cause the needle and cannula topierce the skin of the patient. The same spring, an additional spring,or another similar mechanism may be utilized to retract the needle fromthe patient. In a preferred embodiment, the insertion mechanism maygenerally be as described in International Patent Application No.PCT/US2012/53174, which is included by reference herein in its entiretyfor all purposes. Such a configuration may be utilized for insertion ofthe drug delivery pathway into, or below, the skin (or muscle) of thepatient in a manner that minimizes pain to the patient. Other knownmethods for insertion of a fluid pathway may be utilized and arecontemplated within the bounds of the present invention.

In at least one embodiment, the insertion mechanism 200 includes aninsertion mechanism housing having one or more lockout windows, and abase for connection to the assembly platform and/or pump housing (asshown in FIG. 1B and FIG. 1C). The connection of the base to theassembly platform 20 may be, for example, such that the bottom of thebase is permitted to pass-through a hole in the assembly platform topermit direct contact of the base to the body of the user. In suchconfigurations, the bottom of the base may include a sealing membranethat is removable prior to use of the drug pump 10. The insertionmechanism may further include one or more insertion biasing members, aneedle, a retraction biasing member, a cannula, and a manifold. Themanifold may connect to sterile fluid conduit 30 to permit fluid flowthrough the manifold, cannula, and into the body of the user during drugdelivery.

As used herein, “needle” is intended to refer to a variety of needlesincluding but not limited to conventional hollow needles, such as arigid hollow steel needles, and solid core needles more commonlyreferred to as “trocars.” In a preferred embodiment, the needle is a 27gauge solid core trocar and in other embodiments, the needle may be anysize needle suitable to insert the cannula for the type of drug and drugadministration (e.g., subcutaneous, intramuscular, intradermal, etc.)intended. A sterile boot may be utilized within the needle insertionmechanism. The sterile boot is a collapsible sterile membrane that is infixed engagement at a proximal end with the manifold and at a distal endwith the base. In at least on embodiment, the sterile boot is maintainedin fixed engagement at a distal end between base and insertion mechanismhousing. Base includes a base opening through which the needle andcannula may pass-through during operation of the insertion mechanism, aswill be described further below. Sterility of the cannula and needle aremaintained by their initial positioning within the sterile portions ofthe insertion mechanism. Specifically, as described above, needle andcannula are maintained in the sterile environment of the manifold andsterile boot. The base opening of base may be closed from non-sterileenvironments as well, such as by for example a sealing membrane 254(shown in FIG. 1C).

According to at least one embodiment of the present invention, theinsertion mechanism is initially locked into a ready-to-use stage bylockout pin(s) which are initially positioned within lockout windows ofthe insertion mechanism housing. In this initial configuration,insertion biasing member and retraction biasing member are each retainedin their compressed, energized states. The lockout pin(s) 208 (FIG. 7)may be directly displaced by user depression of the activation mechanism14. As the user disengages any safety mechanisms, such as an optionalon-body sensor 24 (shown in FIG. 1C), the activation mechanism 14 may bedepressed to initiate the drug pump. Depression of the activationmechanism 14 may directly cause translation or displacement of controlarm 40 and directly or indirectly cause displacement of lockout pin(s)208 from their initial position within locking windows of the insertionmechanism housing. Displacement of the lockout pin(s) 208 permitsinsertion biasing member to decompress from its initial compressed,energized state. This decompression of the insertion biasing memberdrives the needle and the cannula into the body of the user. At the endof the insertion stage, the retraction biasing member is permitted toexpand in the proximal direction from its initial energized state. Thisaxial expansion in the proximal direction of the retraction biasingmember retracts the needle, while maintaining the cannula in fluidcommunication with the body of the user. Accordingly, the insertionmechanism may be used to insert a needle and cannula into the user and,subsequently, retract the needle while retaining the cannula in positionfor drug delivery to the body of the user.

Drive Mechanism:

With reference to the embodiments shown in FIGS. 2 and 3, drivemechanism 100 includes a drive housing 130, and a drug container 50having a cap 52, a pierceable seal (not visible), a barrel 58, and aplunger seal 60. A drug chamber 21, located within the barrel 58 betweenthe pierceable seal and the plunger seal 60, may contain a drug fluidfor delivery through the insertion mechanism and drug pump into the bodyof the user. The seals described herein may be comprised of a number ofmaterials but are, in a preferred embodiment, comprised of one or moreelastomers or rubbers. The drive mechanism may further include aconnection mount 54 to guide the insertion of the piercing member of thefluid pathway connection into the barrel 58 of the drug container 50.The drive mechanism 100 may further contain one or more drive biasingmembers, one or more release mechanisms, and one or more guides, as aredescribed further herein. The components of the drive mechanism functionto force a fluid from the drug container out through the pierceableseal, or preferably through the piercing member of the fluid pathwayconnection, for delivery through the fluid pathway connection, sterilefluid conduit, and insertion mechanism into the body of the user.

In one particular embodiment, the drive mechanism 100 employs one ormore compression springs as the biasing member(s). Upon activation ofthe drug pump by the user, the power and control system may be actuatedto directly or indirectly release the compression spring(s) from anenergized state. Upon release, the compression spring(s) may bearagainst and act upon the plunger seal to force the fluid drug out of thedrug container. The compression spring may bear against and act upon apiston which, in turn, acts upon the plunger seal to force the fluiddrug out of the drug container. The fluid pathway connection may beconnected through the pierceable seal prior to, concurrently with, orafter activation of the drive mechanism to permit fluid flow from thedrug container, through the fluid pathway connection, sterile fluidconduit, and insertion mechanism, and into the body of the user for drugdelivery. In at least one embodiment, the fluid flows through only amanifold and a cannula of the insertion mechanism, thereby maintainingthe sterility of the fluid pathway before and during drug delivery. Suchcomponents and their functions are described in further detail herein.

Referring now to the embodiment of the drive mechanism shown in FIG. 2and FIG. 3, the drive mechanism 100 includes a drug container 50 havinga cap 52, a pierceable seal (not visible), a barrel 58, and a plungerseal 60, and optionally a connection mount 54. The drug container 50 ismounted to a distal end of a drive housing 130. Compressed within thedrive housing 130, between the drug container 50 and the proximal end ofthe housing 130, are drive biasing members 122 a and 122 b and a piston110, wherein the drive biasing members 122 a, 122 b are configured tobear upon an interface surface 110C of the piston 110, as describedfurther herein. Optionally, a cover sleeve 140 may be utilized betweenthe drive biasing members 122 and the interface surface 110C of thepiston 110 to, for example, promote more even distribution of force fromthe drive biasing member 122 to the piston 110, prevent buckling of thedrive biasing member 122, and/or hide biasing members 122 from userview. Interface surface 110C of piston 110 is caused to restsubstantially adjacent to, or in contact with, a proximal end of seal60. Although the embodiments shown in FIGS. 2 and 3 show a plurality ofbiasing members it is also contemplated that a single biasing member maybe used.

As best shown in FIG. 3B, the piston 110 may be comprised of twocomponents 110A and 110B and have an interface surface 110C to contactthe plunger seal. A tether, ribbon, string, or other retention strap(referred to herein as the “tether” 580) may be connected at one end tothe piston 110A, 110B. For example, the tether 580 may be connected tothe piston 110A, 110B by retention between the two components of thepiston 110A, 110B when assembled. The tether 580 is connected at anotherend to a winch drum 520 of a delivery control mechanism 500. Through theuse of the winch drum 520 connected to one end of the tether 580, andthe tether 580 connected at another end to the piston 110A, 110B, theregulating mechanism 500 functions to control, meter, provideresistance, or otherwise prevent free axial translation of the piston110A, 110B and plunger seal 60 utilized to force a drug substance out ofa drug container 50. Accordingly, the regulating mechanism 500 and thedrive mechanism 100 (collectively referred to herein as the “controlleddelivery drive mechanism”) together function to control the rate orprofile of drug delivery to the user.

As shown in FIGS. 2 and 3, in the embodiments of the present invention,the regulating mechanism 500 is an escapement regulating mechanism. Theescapement regulating mechanism retards or restrains the distribution oftether 580, only allowing it to advance at a regulated or desired rate.This restricts movement of piston 110 within barrel 58, hencecontrolling the movement of plunger seal 60 and delivery of the drugcontained in chamber 21. As the plunger seal 60 advances in the drugcontainer 50, the drug substance is dispensed through the sterilepathway connection 300, conduit 30, insertion mechanism 200, and intothe body of the user for drug delivery. In turn, tension on tether 580,caused by the force of biasing member 122 on piston 110, imparts atorque on winch drum 520 which is transferred through gear train 510 tothe escapement regulating mechanism. Optionally, a power spring may beincluded, coupled to the escapement regulating mechanism. This may bedone in order to impart additional torque to the winding drum and/orgear train.

In at least one embodiment of the present invention, the drive mechanism100 utilizes an escapement regulating element 500. The regulatingelement 500 further includes one or more gears 512, 514, 516 of a geartrain 510. One or more of the gears 512, 514, 516 may be, for example,compound gears having a small diameter gear attached at a shared centerpoint to a large diameter gear. First gear 512 alternatively referred toas a winch gear, may be rotationally coupled to winch drum 520, forexample by a keyed shaft, thereby coupling rotation of gear train 510 towinch drum 520. First gear 512 engages the small diameter gear 514B ofcompound gear 514 such that rotational movement of the first gear 512 isconveyed by engagement of the gears (such as by engagement ofcorresponding gear teeth) to the compound gear 514. Large gear 514A ofcompound gear 514 engages the small gear 516B of a second compound gear516, conveying rotation thereto. Large gear 516A of second compound gear516 engages small gear 562B of escape wheel 562, thereby couplingrotation of escape wheel 562 to winch drum 520. Rotation of the geartrain 510 may be coupled to winch drum 520 thereby controlling thedistribution of tether 580, and the rate of movement of plunger seal 60within barrel 58 to force a fluid from drug chamber 21. The rotationalmovement of the winch drum 520, and thus the axial translation of thepiston 110 and plunger seal 60, are metered, restrained, or otherwiseprevented from free axial translation by other components of theescapement regulating element 500, as described herein.

The escape wheel 562 is a compound gear having escape teeth around thecircumference of a large diameter escape gear 562A and a small diametergear 562B (not visible) configured to engage the gear train 510 andmeter, restrain, or otherwise prevent free rotational movement thereof.The escapement regulating element 500 further includes a lever 564. Thelever 564 has pins 564A,B and prong 564C. Prong 564C movably engages apost 566A and is configured to removably engage an impulse pin 566B of abalance wheel 566. The balance wheel 566 engages and functions as anoscillator around a pivot point 564D in combination with a hair spring568. The gear train 510, escape wheel 562, balance wheel 566, hairspring 568, and lever 564 may be mounted on and able to freely rotate ormove on a first plate 504 and/or a second plate 506. The first plate 504and second plate 506 may utilize one or more spacer columns to maintainthe desired spacing between components and one or more pivot pins uponwhich the components may be mounted and freely rotated. Anelectromechanical actuator 570 may be provided in addition to or in lieuof the hair spring 568. Electromechanical actuator 570 may be configuredto control and/or adjust the rotation and/or oscillation of balancewheel 566 as will be discussed further hereinafter.

The function of the escape wheel 562, balance wheel 566, hair spring568, and lever 564 components of the escapement regulating element 500are explained with reference to FIG. 2B and FIGS. 4A-4H. The escapewheel 562 and lever 564 may initially be in an activation position, asshown in FIG. 4A. The escape wheel 562 and lever 564 generally functionto perform two steps, termed the locking action and the impulse action.These two actions are illustrated in FIG. 4B and FIG. 4C, respectively,and in which the gear train 510 is applying a clockwise torque on theescape wheel 562. The clockwise torque may come as a result of biasingmembers 122 applying a force to piston 110 which in turn applies atension to tether 580. The tension of tether 580 imparts a torque onwinding drum 520 which is transmitted through gear train 510 to escapewheel 562. Optionally, a power spring may additionally be used to imparttorque to gear train 510. In the locking action, one of two lever pins564A,B blocks escape wheel 562 rotation on the radial face of a tooth onthe escape gear 562A. This locks the gear train 510 between impulseactions. In the impulse action, a lever pin 564A,B slides up to thistooth face due to action of the balance wheel 566 on the lever 564. Theescape wheel becomes unlocked and does mechanical work on the lever pin564A, B via a sliding action, which in turn imparts kinetic energy tothe balance wheel 566. The lever 564 pivots upon a pivot point 564Duntil the opposite pin 564A,B engages with an escape wheel tooth on theescape gear 562A, and the locked state is re-entered after a half toothadvance of the escape wheel 562. The transition from locking action toimpulse action is triggered by the balance wheel 566, which functions asan oscillator in combination with the hair spring 568 and/orelectromechanical actuator 570. It cycles at a natural frequency thatserves as the rate control. Alternatively, the rate can be controlledand/or varied by the electromechanical actuator 570. The balance wheel566 contains an impulse pin 566B which interacts with the lever 564 atprong 564C. For the impulse phase depicted in FIG. 4C, a clockwisemoment on the lever 564 exerts a counterclockwise moment on the balancewheel 566, adding to its kinetic energy. The balance wheel 566 rotatesuntil its kinetic energy is absorbed by the hair spring 568 or until itis caused to stop by electromechanical actuator 570. It stops, reverses,and reengages the impulse pin 566B with the lever 564. A complete cycleis shown in the transition between FIGS. 4D-4H. For example, a motor(e.g., a DC motor, AC motor, or stepper motor) or a solenoid (e.g.,linear solenoid, rotary solenoid) may be used to rotate the balancewheel. This electromechanical actuator may be used in addition to thehair spring or in place of the hair spring. The electromechanicalactuator may be controlled by the power and control system. By providingan electromechanical actuator the rate of drug delivery may be adjustedand/or controlled. In one embodiment, electromechanical actuator 570 isa rotary solenoid. Upon receipt of an input signal from the power andcontrol system the core of the rotary solenoid may rotate. This rotationmay be imparted to balancing wheel 566 by, for example, a keyed shaft.The rotary solenoid may later, upon either removal of the input signalor the receipt of a second input signal, rotate the balancing wheel backin the opposite direction or, alternatively, a hair spring may be usedto return the balancing wheel in the opposite direction. This actioncould similarly be performed by a linear solenoid using an appropriatelinkage to convert the linear motion of the solenoid core to rotationalmotion of the balancing wheel. A motor may also be configured to performsimilarly.

To unlock the escapement regulating mechanism 500, the balance wheel 566must have enough kinetic energy to drag the lever pin 564A,B up the faceof the tooth of the escape gear 562A of the escape wheel 562. If theimpulse action adds less energy than is lost to friction, the balancewheel 566 will rotate less and less and finally stall, locking theescapement regulating mechanism 500. If the escapement stops in this wayunder load, it will not restart easily. To be self-starting, the hairspring 568 must align the lever 564 along the axis connecting the pivotof the escape wheel 562 and the pivot of the balance wheel 566, as shownin FIG. 4A. The lever pins 564A,B will be positioned so that a beveltooth face can immediately start an impulse action upon application of adrive torque. This alignment can occur only with the escapementregulating mechanism 500 in an unloaded state. The tension on the tetherprovided by the force of the biasing member 122 on the piston 110 mustbe isolated from the escapement regulating mechanism 500 until the startof delivery. This may be done by, for example, providing a lock-outfeature which, in a first configuration, prevents motion of piston 110.After transformation to a second configuration, the lock-out featuredoes not prevent motion of piston 110 and thereafter the tension ontether 580 acts to create a torque on winding drum 520. Alternatively,escapement regulating mechanism 500 may be initiated by a user impartinga force on an activation mechanism and, directly or indirectly through apower and control system, applying a drive torque to start the initialimpulse action. Once the escapement regulating mechanism 500 isinitiated, it can be effectively utilized to meter, restrain, orotherwise prevent free rotational movement of the gear train 510,winding drum 520 and piston 110, and, thus, plunger seal 60. In aparticular embodiment, the escape wheel 562 is a compound gear havingescape teeth around the circumference of a large diameter escape gear562A and a small diameter gear 562B (not visible). The small diametergear 562B of the escape wheel 562 engages the drive train 510, whichengages with winding drum 520 through rotation shaft 518. This novelconfiguration directly permits the escape wheel 562 to regulate therotation of the drive train 510 and winding drum 520, which thenefficiently regulates the tether 580 and the piston 110.

Notably, the regulating mechanisms 500 of the present invention do notdrive the delivery of fluid substances from the drug chamber 21. Thedelivery of fluid substances from the drug chamber 21 is caused by theexpansion of the biasing member 122 from its initial energized stateacting upon the piston 110A, 110B and plunger seal 60. The regulatingmechanisms 500 instead function to provide resistance to the free motionof the piston 110A, 110B and plunger seal 60 as they are pushed by theexpansion of the biasing member 122 from its initial energized state.The regulating mechanism 500 does not drive the delivery but onlycontrols the delivery motion. The tether limits or otherwise restrainsthe motion of the piston 110 and plunger seal 60, but does not apply theforce for the delivery. According to a preferred embodiment, thecontrolled delivery drive mechanisms and drug pumps of the presentinvention include an escapement regulating mechanism indirectly ordirectly connected to a tether metering the axial translation of thepiston 110A, 110B and plunger seal 60, which are being driven to axiallytranslate by the biasing member 122. The rate of drug delivery ascontrolled by the regulating mechanism may be determined by: selectionof the gear ratio of gear train 510; selection of the spring rate ofhair spring 568; selection of the diameter of winding drum 520; usingelectromechanical actuator 570 to control the rate of oscillation and/orrotation of balance wheel 566; or any other method known to one skilledin the art. By using electromechanical actuator 570 to control theoscillation and/or rotation of balance wheel 566 it may be possible toconfigure a drug pump to provide a variable dose rate (i.e., the rate ofdrug delivery is varied during a treatment).

In another embodiment, the power and control system of the drug pump isconfigured to receive one or more inputs to meter the release of thetether 580 by the winch drum 520 and thereby permit axial translation ofthe piston 110 by the biasing member 122 to translate a plunger seal 60within a barrel 58. The one or more inputs may be provided by theactuation of the activation mechanism 14, a control interface, and/or aremote control mechanism. The power and control system may be configuredto receive one or more inputs to adjust the restraint provided by thetether 580 and winch drum 520 on the free axial translation of thepiston 110 upon which the biasing member 122 bears upon to meet adesired drug delivery rate or profile, to change the dose volume fordelivery to the user, and/or to otherwise start, stop, or pauseoperation of the drive mechanism.

The components of the drive mechanism 100, upon activation, may be usedto drive axial translation in the distal direction of the plunger seal60 of the drug container 50. Optionally, the drive mechanism 100 mayinclude one or more compliance features which enable additional axialtranslation of the plunger seal 60 to, for example, ensure thatsubstantially the entire drug dose has been delivered to the user. Forexample, the plunger seal 60, itself, may have some compressibilitypermitting a compliance push of drug fluid from the drug container.

The novel controlled delivery drive mechanisms of the present inventionmay optionally integrate status indication into the drug dose delivery.By use of one or more status triggers 580A and a corresponding statusreader 544, the status of the drive mechanism before, during, and afteroperation can be relayed to the power and control system to providefeedback to the user. Such feedback may be tactile, visual, and/orauditory, as described above, and may be redundant such that more thanone signal or type of feedback is provided to the user during use of thedevice. For example, the user may be provided an initial feedback toidentify that the system is operational and ready for drug delivery.Upon activation, the system may then provide one or more drug deliverystatus indications to the user. At completion of drug delivery, thedrive mechanism and drug pump may provide an end-of-dose indication. Asthe end-of-dose indication is tied to the piston reaching the end of itsaxial translation, the drive mechanism and drug pump provide a trueend-of-dose indication to the user.

The tether 580 may have one or more status triggers, such as electricalcontacts, optical markings, or electromechanical pins or recesses, whichare capable of contacting or being recognized by a status reader. In atleast one embodiment, an end-of-dose status indication may be providedto the user once the status reader contacts or recognizes the finalstatus trigger positioned on the tether 580 that would contact thestatus reader at the end of axial travel of the piston 110A, 110B andplunger 60 within the barrel 58 of the drug container 50. The statusreader may be, for example, an electrical switch reader to contact thecorresponding electrical contacts, an optical reader to recognize thecorresponding optical markings, or a mechanical or electromechanicalreader configured to contact corresponding pins, holes, or similaraspects on the tether. The status triggers may be positioned along thetether 580 to be read or recognized at positions which correspond withthe beginning and end of drug delivery, as well as at desired incrementsduring drug delivery. As the drug pump is activated and drug delivery isbegun by release of the biasing member 122 and the resulting forceapplied to the piston 110A, 110B and plunger seal 60, the rate orprofile of drug delivery to the user is controlled by the escapementregulating mechanism, gear assembly, and winch drum 520 releasing thetether 580 and permitting expansion of the biasing member 122 and axialtranslation of the piston 110A, 110B and plunger seal 60. As thisoccurs, the status triggers of the tether 580 are contacted orrecognized by the status reader and the status of the drive mechanismbefore, during, and after operation can be relayed to the power andcontrol system to provide feedback to the user. Depending on the numberof status triggers located on the tether 580, the frequency of theincremental status indication may be varied as desired. As describedabove, a range of status readers may be utilized depending on the statustriggers utilized by the system.

In a preferred embodiment, the status reader may apply a tensioningforce to the tether 580. When the system reaches end-of-dose, the tether580 goes slack and the status reader 544 is permitted to rotate about afulcrum. This rotation may operate an electrical or electromechanicalswitch, for example a switch, signaling slack in the tether 580 to thepower and control system. Additionally, a gear of gear train 510 may actas an encoder along with a sensor. The sensor/encoder combination isused to provide feedback of gear train rotation, which in turn can becalibrated to the position of piston 110 when there is no slack in thetether 580. Together, the status reader and sensor/encoder may providepositional feedback, end-of-dose signal, and error indication, such asan occlusion, by observing slack in the tether 580 prior to reaching theexpected number of motor rotations as counted by the sensor/encoder.

Further aspects of the novel drive mechanism will be described withreference to FIGS. 5A-5B and 6A-6C. FIG. 5A shows an isometric view ofthe drive mechanism, according to at least a first embodiment, duringits initial locked stage. A fluid, such as a drug fluid, may becontained within barrel 58, in a drug chamber 21 between plunger seal 60and a pierceable seal (not visible), for delivery to a user. Thepierceable seal is adjacent or retained at least partially within cap52. Upon activation by the user, a fluid pathway connection may beconnected to the drug container through the pierceable seal 56. Asdescribed above, this fluid connection may be facilitated by a piercingmember of the fluid pathway connection which pierces the pierceable sealand completes the fluid pathway from the drug container, through thefluid pathway connection, the fluid conduit, the insertion mechanism,and the cannula for delivery of the drug fluid to the body of the user.Initially, one or more locking mechanisms (not shown) may retain thebiasing member 122 in an initial energized position within piston 110A,110B. Directly or indirectly upon activation of the device by the user,the locking mechanism may be removed to permit operation of the drivemechanism. Removal of the locking mechanism may permit the biasingmember to impart a force to piston 110 and therefore to tether 580. Thisforce on tether 580 imparts a torque on winding drum 520 which causesthe gear train and escapement regulating mechanism to begin motion. Asshown in FIG. 6A, the piston 110 and biasing member 122 are bothinitially in a compressed, energized state behind the plunger seal 60.The biasing member 122 may be maintained in this state until activationof the device between internal features of drive housing 130 andinterface surface 110C of piston 110A, 110B. As the locking mechanism isremoved or displaced, biasing member 122 is permitted to expand (i.e.,decompress) axially in the distal direction (i.e., in the direction ofthe hatched arrow). Such expansion causes the biasing member 122 to actupon and distally translate interface surface 110C and piston 110,thereby distally translating plunger seal 60 to push drug fluid out ofthe drug chamber 21 of barrel 58.

As shown in FIG. 6B, such distal translation of the piston 110A, 110Band plunger seal 60 continues to force fluid flow out from barrel 58through the pierceable seal 56. In at least one embodiment, anend-of-dose status indication may be provided to the user once thestatus reader contacts or recognizes a status trigger positioned on thetether 580 to substantially correspond with the end of axial travel ofthe piston 110A, 110B and plunger seal 60 within the barrel 58 of thedrug container 50. The status triggers are positioned along the tether580 at various increments, such as increments which correspond tocertain volume measurement, to provide incremental status indication tothe user. In at least one embodiment, the status reader is an opticalstatus reader configured to recognize the corresponding optical statustriggers on the tether. As would be understood by an ordinarily skilledartisan, such optical status triggers may be markings which arerecognizable by the optical status reader. In another embodiment, thestatus reader is a mechanical or electromechanical reader configured tophysically contact corresponding pins, holes, or similar aspects on thetether. Electrical contacts could similarly be utilized on the tether asstatus indicators which contact or are otherwise recognized by thecorresponding electrical status reader. The status triggers may bepositioned along the tether 580 to be read or recognized at positionswhich correspond with the beginning and end of drug delivery, as well asat desired increments during drug delivery. As shown, tether 580 passessubstantially axially through the drive mechanism housing 130, thebiasing member 122, and connects to the piston 110A, 110B to restrictthe axial translation of the piston 110A, 110B and the plunger seal 60that resides adjacent thereto.

The novel embodiments of the present invention may be utilized to meter,restrain, or otherwise prevent free rotational movement of winding drum520 and, thus, axial translation of the components of the controlleddelivery drive mechanism 100. Accordingly, the escapement regulatingmechanism 500 only controls the motion of the drive mechanism, but doesnot apply the force for the drug delivery. One or more additionalbiasing members 122, such as compression springs, may be utilized todrive or assist the driving of the piston 110. For example, acompression spring may be utilized within the drive housing 130 for thispurpose. The escapement regulating mechanism 500 only controls, meters,or regulates such action. A mechanical timing system, such as theescapement regulating mechanism described herein, may be utilized toallow the piston 110 and plunger seal 60 to translate axially acontrolled distance, or a controlled volume, and may be utilized to meeta desired delivery rate or profile. The timing system can be controlledby quartz timing instead of mechanical timing, as would be appreciatedby one having ordinary skill in the art. For quartz timing, a batteryprovides power to a microchip and circuit. The quartz crystal oscillatesat a precise frequency. Alternate electrical timing mechanisms such as,for example, RC timing mechanisms, may also be used, including clockfunctions commonly found in microprocessors. Depending on the periodthat the delivery is planned to occur over, the microchip drives a motorbased on a number of quartz crystal oscillations or other timingsignals. The motor releases motion of a drive train to control the axialtranslation of a plunger in a similar manner as described herein for themechanical timing system.

The delivery control mechanisms 500 of the present invention do notdrive the delivery of fluid substances from the drug chamber 21. Thedelivery of fluid substances from the drug chamber 21 is caused by theexpansion of the biasing member 122 from its initial energized stateacting upon the piston 110A, 110B and plunger seal 60. The deliverycontrol mechanisms 500 instead function to provide resistance to thefree motion of the piston 110A, 110B and plunger seal 60 as they arepushed by the expansion of the biasing member 122 from its initialenergized state. As the delivery control mechanisms 500 release thetether 580, the biasing member 122 is permitted to continue itsexpansion from its energized state and drive the piston 110A, 110B andplunger seal 60 until the plunger seal 60 has substantially contactedthe pierceable seal 56. This is visible in the cross-sectional viewprovided in FIG. 6C. At this point, substantially all of the drugsubstance has been pushed out of the drug chamber 21 through the fluidpathway connection 300 for drug delivery to the user. A status triggermay be configured along the tether 580 to correspond with this positionof the piston 110A, 110B, such that, as the piston 110A, 110B reachesits end of axial travel, a status trigger is read or recognized by thestatus reader to provide true end-of-dose indication to the user. Asstated above, the status triggers may be positioned along the tether 580to be read or recognized at positions which correspond with thebeginning and end of drug delivery, as well as at desired incrementsduring drug delivery. The controlled delivery drive mechanisms and/ordrug pumps of the present invention may additionally enable a compliancepush to ensure that substantially all of the drug substance has beenpushed out of the drug chamber 21. The plunger seal 60, itself, may havesome compressibility permitting a compliance push of drug fluid from thedrug container. For example, when a pop-out plunger seal is employed,i.e., a plunger seal that is deformable from an initial state, theplunger seal may be caused to deform or “pop-out” to provide acompliance push of drug fluid from the drug container, as shown in FIG.6C. Additionally or alternatively, an electromechanical status switchand interconnect assembly may be utilized to contact, connect, orotherwise enable a transmission to the power and control system tosignal end-of-dose to the user. For example, the status switch may belocated distal to the pierceable seal 56 and the interconnect locatedproximal to the plunger seal 60 such that, upon substantially completeaxial translation (and optional compliance push) of the plunger seal 60within the barrel 58, the status switch and interconnect coordinate toenable a transmission to the power and control system to signalend-of-dose to the user. This configuration further enables trueend-of-dose indication to the user.

In at least one embodiment, incremental status indication may beprovided to the user by reading or recognizing the rotational movementof one or more gears of gear train 510. As the gear train 510 rotates, astatus reader may read or recognize one or more corresponding statustriggers on one of the gears in the gear train to provide incrementalstatus indication before, during, and after operation of the variablerate controlled delivery drive mechanism. A number of status readers maybe utilized within the embodiments of the present invention. Forexample, the drive mechanism may utilize a mechanical status readerwhich is physically contacted by gear teeth of one of the gears of thegear train. As the status reader is contacted by the status trigger(s),which in this exemplary embodiment may be the gear teeth of one of thegears (or holes, pins, ridges, markings, electrical contacts, or thelike, upon the gear), the status reader measures the rotational positionof the gear and transmits a signal to the power and control system forstatus indication to the user. Additionally or alternatively, the drivemechanism may utilize an optical status reader. The optical statusreader may be, for example, a light beam that is capable of recognizinga motion and transmitting a signal to the power and control system. Forexample, the drive mechanism may utilize an optical status reader thatis configured to recognize motion of the gear teeth of one of the gearsin the gear train (or holes, pins, ridges, markings, electricalcontacts, or the like, upon the gear). Similarly, the status reader maybe an electrical switch configured to recognize electrical contacts onthe gear. In any of these embodiments, the sensor may be utilized tothen relay a signal to the power and control system to provide feedbackto the user.

As would be appreciated by one having ordinary skill in the art, opticalstatus readers and corresponding triggers, electromechanical statusreaders and corresponding triggers, and/or mechanical status readers andcorresponding triggers may all be utilized by the embodiments of thepresent invention to provide incremental status indication to the user.While the drive mechanisms of the present invention are described withreference to the gear train and escapement regulating mechanism shown inthe figures, a range of configurations may be acceptable and capable ofbeing employed within the embodiments of the present invention, as wouldreadily be appreciated by an ordinarily skilled artisan. Accordingly,the embodiments of the present invention are not limited to the specificgear train and escapement regulating mechanism described herein, whichis provided as an exemplary embodiment of such mechanisms for employmentwithin the controlled delivery drive mechanisms and drug delivery pumps.

Assembly and/or manufacturing of controlled delivery drive mechanism100, drug delivery pump 10, or any of the individual components mayutilize a number of known materials and methodologies in the art. Forexample, a number of known cleaning fluids such as isopropyl alcohol andhexane may be used to clean the components and/or the devices. A numberof known adhesives or glues may similarly be employed in themanufacturing process. Additionally, known siliconization and/orlubrication fluids and processes may be employed during the manufactureof the novel components and devices. Furthermore, known sterilizationprocesses may be employed at one or more of the manufacturing orassembly stages to ensure the sterility of the final product.

The drive mechanism may be assembled in a number of methodologies. Inone method of assembly, the drug container 50 may first be assembled andfilled with a fluid for delivery to the user. The drug container 50includes a cap 52, a pierceable seal 56, a barrel 58, and a plunger seal60. The pierceable seal 56 may be fixedly engaged between the cap 52 andthe barrel 58, at a distal end of the barrel 58. The barrel 58 may befilled with a drug fluid through the open proximal end prior toinsertion of the plunger seal 60 from the proximal end of the barrel 58.An optional connection mount 54 may be mounted to a distal end of thepierceable seal 56. The connection mount 54 may guide the insertion ofthe piercing member of the fluid pathway connection into the barrel 58of the drug container 50. The drug container 50 may then be mounted to adistal end of drive housing 130.

One or more drive biasing members 122 may be inserted into a distal endof the drive housing 130. Optionally, a cover sleeve 140 may be insertedinto a distal end of the drive housing 130 to substantially coverbiasing member 122. A piston may be inserted into the distal end of thedrive housing 130 such that it resides at least partially within anaxial pass-through of the biasing member 122 and the biasing member 122is permitted to contact a piston interface surface 110C of piston 110A,110B at the distal end of the biasing member 122. An optional coversleeve 140 may be utilized to enclose the biasing member 122 and contactthe piston interface surface 110C of piston 110A, 110B. The piston 110A,110B and drive biasing member 122, and optional cover sleeve 140, may becompressed into drive housing 130. Such assembly positions the drivebiasing member 122 in an initial compressed, energized state andpreferably places a piston interface surface 110C in contact with theproximal surface of the plunger seal 60 within the proximal end ofbarrel 58. The piston, piston biasing member, contact sleeve, andoptional components, may be compressed and locked into theready-to-actuate state within the drive housing 130 prior to attachmentor mounting of the drug container 50. The tether 580 is pre-connected tothe proximal end of the piston 110A, 110B and passed through the axialaperture of the biasing member 122 and drive mechanism 130, and thenwound through the interior of the drug pump with the other end of thetether 580 wrapped around the winch drum 520 of the regulating mechanism500.

A fluid pathway connection, and specifically a sterile sleeve of thefluid pathway connection, may be connected to the cap and/or pierceableseal of the drug container. A fluid conduit may be connected to theother end of the fluid pathway connection which itself is connected tothe insertion mechanism such that the fluid pathway, when opened,connected, or otherwise enabled travels directly from the drugcontainer, fluid pathway connection, fluid conduit, insertion mechanism,and through the cannula for drug delivery into the body of a user. Thecomponents which constitute the pathway for fluid flow are nowassembled. These components may be sterilized, by a number of knownmethods, and then mounted either fixedly or removably to an assemblyplatform or housing of the drug pump, as shown in FIG. 1B.

Certain optional standard components or variations of drive mechanism100 or drug pump 10 are contemplated while remaining within the breadthand scope of the present invention. For example, the embodiments mayinclude one or more batteries utilized to power a motor or solenoid,drive mechanisms, and drug pumps of the present invention. A range ofbatteries known in the art may be utilized for this purpose.Additionally, upper or lower housings may optionally contain one or moretransparent or translucent windows 18, as shown in FIG. 1A, to enablethe user to view the operation of the drug pump 10 or verify that drugdose has completed. Similarly, the drug pump 10 may contain an adhesivepatch 26 and a patch liner 28 on the bottom surface of the housing 12.The adhesive patch 26 may be utilized to adhere the drug pump 10 to thebody of the user for delivery of the drug dose. As would be readilyunderstood by one having ordinary skill in the art, the adhesive patch26 may have an adhesive surface for adhesion of the drug pump to thebody of the user. The adhesive surface of the adhesive patch 26 mayinitially be covered by a non-adhesive patch liner 28, which is removedfrom the adhesive patch 26 prior to placement of the drug pump 10 incontact with the body of the user. Removal of the patch liner 28 mayfurther remove the sealing membrane 254 of the insertion mechanism 200,opening the insertion mechanism to the body of the user for drugdelivery (as shown in FIG. 1C).

Similarly, one or more of the components of controlled delivery drivemechanism 100 and drug pump 10 may be modified while remainingfunctionally within the breadth and scope of the present invention. Forexample, as described above, while the housing of drug pump 10 is shownas two separate components upper housing 12A and lower housing 12B,these components may be a single unified component. As discussed above,a glue, adhesive, or other known materials or methods may be utilized toaffix one or more components of the controlled delivery drive mechanismand/or drug pump to each other. Alternatively, one or more components ofthe controlled delivery drive mechanism and/or drug pump may be aunified component. For example, the upper housing and lower housing maybe separate components affixed together by a glue or adhesive, a screwfit connection, an interference fit, fusion joining, welding, ultrasonicwelding, and the like; or the upper housing and lower housing may be asingle unified component. Such standard components and functionalvariations would be appreciated by one having ordinary skill in the artand are, accordingly, within the breadth and scope of the presentinvention.

It will be appreciated from the above description that the controlleddelivery drive mechanisms and drug pumps disclosed herein provide anefficient and easily-operated system for automated drug delivery from adrug container. The novel embodiments described herein provide drivemechanisms for the controlled delivery of drug substances and drugdelivery pumps which incorporate such controlled delivery drivemechanisms. The drive mechanisms of the present invention control therate of drug delivery by metering, providing resistance, or otherwisepreventing free axial translation of the plunger seal utilized to forcea drug substance out of a drug container and, thus, are capable ofdelivering drug substances at variable rates and/or delivery profiles.Additionally, the drive mechanisms of the present invention may provideintegrated status indication features which provide feedback to the userbefore, during, and after drug delivery. For example, the user may beprovided an initial feedback to identify that the system is operationaland ready for drug delivery. Upon activation, the system may thenprovide one or more drug delivery status indications to the user. Atcompletion of drug delivery, the drive mechanism and drug pump mayprovide an end-of-dose indication. The novel controlled delivery drivemechanisms of the present invention may be directly or indirectlyactivated by the user. Furthermore, the novel configurations of thecontrolled delivery drive mechanism and drug pumps of the presentinvention maintain the sterility of the fluid pathway during storage,transportation, and through operation of the device. Because the paththat the drug fluid travels within the device is entirely maintained ina sterile condition, only these components need be sterilized during themanufacturing process. Such components include the drug container of thedrive mechanism, the fluid pathway connection, the sterile fluidconduit, and the insertion mechanism. In at least one embodiment of thepresent invention, the power and control system, the assembly platform,the control arm, the activation mechanism, the housing, and othercomponents of the drug pump do not need to be sterilized. This greatlyimproves the manufacturability of the device and reduces associatedassembly costs. Accordingly, the devices of the present invention do notrequire terminal sterilization upon completion of assembly.

Manufacturing of a drug pump includes the step of attaching both thecontrolled delivery drive mechanism and drug container, eitherseparately or as a combined component, to an assembly platform orhousing of the drug pump. The method of manufacturing further includesattachment of the fluid pathway connection, drug container, andinsertion mechanism to the assembly platform or housing. The additionalcomponents of the drug pump, as described above, including the power andcontrol system, the activation mechanism, and the control arm may beattached, preformed, or pre-assembled to the assembly platform orhousing. An adhesive patch and patch liner may be attached to thehousing surface of the drug pump that contacts the user during operationof the device.

A method of operating the drug pump includes the steps of: activating,by a user, the activation mechanism; displacing a control arm to actuatean insertion mechanism; and actuating a power and control system toactivate a controlled delivery drive mechanism to drive fluid drug flowthrough the drug pump according to a controlled rate or drug deliveryprofile. The method may further include the step of: engaging anoptional on-body sensor prior to activating the activation mechanism.The method similarly may include the step of: establishing a connectionbetween a fluid pathway connection to a drug container. Furthermore, themethod of operation may include translating a plunger seal within thecontrolled delivery drive mechanism by the expansion of the biasingmember acting upon a piston within a drug container to force fluid drugflow through the drug container, the fluid pathway connection, a sterilefluid conduit, and the insertion mechanism for delivery of the fluiddrug to the body of a user, wherein a regulating mechanism acting torestrain the distribution of a tether is utilized to meter the freeaxial translation of the piston. The method of operation of theinsertion mechanism and the drug pump may be better appreciated withreference to FIGS. 5A-5B and FIGS. 6A-6C, as described above.

Throughout the specification, the aim has been to describe the preferredembodiments of the invention without limiting the invention to any oneembodiment or specific collection of features. Various changes andmodifications may be made to the embodiments described and illustratedwithout departing from the present invention. The disclosure of eachpatent and scientific document, computer program and algorithm referredto in this specification is incorporated by reference in its entirety.

What is claimed is:
 1. A controlled delivery drive mechanism for a drugdelivery pump, comprising: a drive housing; a piston having an interfacesurface; at least one biasing member initially retained in an energizedstate and configured to bear upon the interface surface of the piston; atether connected at one end to the piston and at another end to a winchdrum, the tether configured to restrain expansion of the at least onebiasing member; and an escapement regulating mechanism configured tometer release of the tether by the winch drum, wherein release of the atleast one biasing member from the initial energized state appliestension to the tether, the tension to the tether imparting a drivetorque to the escapement regulating mechanism and initiating an impulseaction of the escapement regulating mechanism to initiate the meteredrelease of the tether, the metered release of the tether providing forcontrolled expansion of the at least one biasing member.
 2. Thecontrolled delivery drive mechanism of claim 1, further comprising: adrug container having a plunger seal located within a barrel, whereinthe piston is configured to axially translate the plunger seal withinthe barrel.
 3. The controlled delivery drive mechanism of claim 2,wherein the drug container contains a drug fluid within a drug chamberof the barrel.
 4. The controlled delivery drive mechanism of claim 1,wherein the metering of the tether by the escapement regulatingmechanism controls a rate or profile of drug delivery to a user.
 5. Thecontrolled delivery drive mechanism of claim 1, wherein the escapementregulating mechanism comprises a gear train having one or more gears,wherein rotation of at least one gear of the gear train is coupled torotation of the winch drum.
 6. The controlled delivery drive mechanismof claim 5, wherein the escapement regulating mechanism furthercomprises a lever and an escape wheel configured to engage with the geartrain and meter rotational movement of the gear train.
 7. The controlleddelivery drive mechanism of claim 6, wherein the escape wheel is acompound gear including at least two escape gears of different diameter,one of the at least two escape gears comprising escape teeth and anotherof the at least two escape gears configured to engage with the geartrain.
 8. The controlled delivery drive mechanism of claim 6, whereinthe lever includes pins and a prong, the prong configured to moveablyengage a post and an impulse pin of a balance wheel, the balance wheelconfigured to oscillate about the post in combination with a hairspring.
 9. The controlled delivery drive mechanism of claim 8 furthercomprising an actuator that at least partially controls oscillation ofthe balance wheel.
 10. The controlled delivery drive mechanism of claim9, wherein the actuator is a mechanical actuator, an electricalactuator, or an electromechanical actuator.
 11. The controlled deliverydrive mechanism of claim 6, wherein the gear train comprises a winchgear rotationally coupled to the winch drum and configured to engage atleast one compound gear, the at least one compound gear configured toengage directly or indirectly with the escape wheel, the at least onecompound gear thereby coupling rotation of the escape wheel to rotationof the winch drum.
 12. The controlled delivery drive mechanism of claim1, further comprising a status reader configured to recognize one ormore status triggers incrementally spaced on the tether.
 13. Thecontrolled delivery drive mechanism of claim 12, wherein the statusreader is an optical status reader and the one or more status triggersare optical status triggers.
 14. The controlled delivery drive mechanismof claim 12, wherein the status reader is an electromechanical statusreader and the one or more status triggers are electromechanical statustriggers.
 15. The controlled delivery drive mechanism of claim 1,wherein the escapement regulating mechanism is configured to transitionbetween the impulse action and a locking action based on oscillatingmovement of a balance wheel.
 16. The controlled delivery drive mechanismof claim 15, wherein a rate of oscillation of the balance wheel providesfor a rate of metered release of the tether.
 17. A drug delivery pumpcomprising: a housing; an insertion mechanism; a fluid pathwayconnection; a power and control system; and a controlled delivery drivemechanism comprising: a drive housing; a piston having an interfacesurface; at least one biasing member initially retained in an energizedstate and configured to bear upon the interface surface of piston; atether connected at one end to the piston and at another end to a winchdrum, the tether configured to restrain expansion of the at least onebiasing member; and an escapement regulating mechanism configured tometer release of the tether by the winch drum, wherein release of the atleast one biasing member from the initial energized state appliestension to the tether, the tension to the tether imparting a drivetorque to the escapement regulating mechanism and initiating an impulseaction of the escapement regulating mechanism to initiate the meteredrelease of the tether, the metered release of the tether providing forcontrolled expansion of the at least one biasing member; wherein thepower and control system is configured to receive one or more inputs tometer the release of tether by the winch drum and permit axialtranslation of the piston by the biasing member.
 18. The drug deliverypump of claim 17, wherein the one or more inputs are received from anactivation mechanism configured to be acted upon by a user.
 19. The drugdelivery pump of claim 17, wherein the power and control system isconfigured to adjust an amount of restraint provided by the tether andwinch drum on the axial translation of the piston to start, stop, orpause operation of the drive mechanism based on the one or more inputs.20. The drug delivery pump of claim 17, wherein the power and controlsystem is configured to adjust an amount of restraint provided by thetether and winch drum on the axial translation of the piston to change adose volume or a delivery rate for delivery to a user based on the oneor more inputs.